March 14, 1901] 



NA TURE 



479 



Mountain Air. — With the object just referred to, the next 

 station selected was in the Pyrenees on the Pic Canigou, a 

 barren mountain 2785 metres in height. The transport of the 

 apparatus to this remote station required six porters and mules, 

 and M. Gautier with his pr^parateur and one guide were left to 

 make the best of a rock cabin amidst the snow, fires being sup- 

 pressed in order to avoid contamination of the atmosphere. 



Under these cheerless conditions a series of determinations 

 was made which amply realised the anticipation that in the 

 absence of vegetation and soil the proportion of marsh gas 

 would diminish. The quanticy found was 2 '19 volumes per 

 100,000 as against 11 '3 for the air of woods and 22 6 for the 

 air of Paris. 



The quantity of free hydrogen reached 17 parts per 100,000. 



Sea Air.—M. Gautier now decided to get rid of vegetation 

 altogether by going out to sea, and took up his station during 

 the autumn equinox at the iron lighthouse of the Roches- 

 Douvres, 40 kilometres from the coast of Brittany. He arrived 

 after a series of north-west gales, and was, he says, altogether 

 tn's favorisd par les circonstances. Analysis showed a fall in the 

 proportion of carbon to 1/33 of what it was in mountain air, that 

 is, to an almost negligible quantity. There was an increase in 

 the amount of free hydrogen to 19*5 vols, per 100,000. It 

 appears, therefore, that the air over the sea and at very high 

 altitudes is nearly free from hydrocarbons, and that it contains 

 two vols, in 10,000 of free hydrogen, a proportion, it will be 

 observed, about two-thirds of that of the atmospheric carbonic 

 acid. 



Source of the Gases. — In the concluding section of his memoir, 

 M. Gautier discusses in more detail the nature of the accessory 

 combustible gases in the air and the origin of atmospheric 

 hydrogen. He concludes that, subject to variations, the com- 

 bustible gases of Paris air may be set down as follows, in 

 volumes per 100,000 : — Free hydrogen I9'4, methane I2'i, 

 benzene vapour or analogous compounds i "j, carbon monoxide 

 and traces of defines and acetylenes "2. 



It remains now only to show that the presence of hydrocarbons 

 in air is in accordance with established geological facts, and 

 that it is connected with the occurrence of the larger quantities 

 of free hydrogen. M. Gautier points out that methane is 

 exhaled from many soils, that it is the chief constituent of fire- 

 damp, that it occurs with petroleum and is emitted by volcanoes, 

 especially by mud volcanoes. Hydrogen often accompanies 

 methane in these cases, and has been found in the fumerolles of 

 Iceland and Tuscany. These outbursts are only extreme 

 manifestations of actions which have been silently in continual 

 progress for ages. The occurrence of hydrogen occluded in 

 rocks has been pointed out by Fouque and by Tilden. 

 M. Gautier has himself greatly extended earlier researches. 

 He finds that many specimens of granite treated with water at 

 280° C. or with dilute acids at 100°, yield a considerable 

 volume of gas. Thus, in one case, a kilogramme of granite 

 heated with diluted phosphoric acid gave the following volumes 

 in c.c. :— HjS I'z, €02272-6, C^llo 12*3, CH4 trace, Ng (rich 

 in argon) 230-5, Hg 53. ' 



It seems probable that when the igneous rocks were solidify- 

 ing and their components crystallising, they included small 

 quantities of the primitive earth materials which now form the 

 subjacent zone, that is to say, sulphides, nitrides, argonides, 

 heliides, hydrocarbons, carbides, fluorides, iodides, phosphides, 

 arsenides, &c. These substances, by the action of water, aided 

 or not by acids, gave rise to the observed gases. As to the 

 hydrogen, M. Gautier is assured by experiments, which he does 

 not now detail, that it comes from {a) the action of water at a 

 red heat on ferrous compounds, (b) the destruction by heat of 

 hydrocarbons formed previpusly by the action of water on 

 metallic carbides, [c) in a less degree by the action of water at 

 a red heat on certain nitrides. 



Hydrocarbons come from the action of water on small 

 quantities of metallic carbides, especially those of aluminium 

 and iron, included in the rocks. 



Many more details of geological and chemical interest are 

 given by M. Gautier. He insists that it is not necessary to 

 imagine that water penetrates to the molten material lying 

 below the solid crust of the earth. It is sufficient for the water 

 to reach the low layers of rock containing these small quantities 

 of included raw materials. On the other hand, it is not to be 

 supposed that the gaseous products of the action of water on the 

 raw materials will all escape from the surface. Some of the 

 gases will combine with the rocks, and some on reaching the 



NO. 1637. VOL. 63] 



region of oxygen will be oxidised ; but others, including methane, 

 the petroleum hydrocarbons, nitrogen and hydrogen, not 

 readily oxidised except at high temperatures, will escape into 

 the air. 



M. Gautier deals briefly with the question as to whether the 

 hydrogen will tend to accumulate in the upper regions of the 

 atmosphere. Without committing himself to a definite opinion, 

 he quotes the views of Dr. Johnstone Stoney as to the impossi- 

 bility of the earth's gravitational attraction being sufficient to 

 retain helium or hydrogen. If the view is accepted that some 

 of the hydrogen molecules at the fringe of the atmosphere have 

 a velocity outwards of 11,000 metres per second, their escape 

 would be possible, and we should have to picture a continual 

 flux of hydrogen from the earth's surface through the atmosphere 

 into interstellar space. 



It is interesting to note that Profs. Liveing and Dewar incline 

 perhaps to a different view. They say "if the earth cannot 

 retain hydrogen or originate it, then there must be a continued 

 accession of hydrogen to the atmosphere (from interplanetary 

 space), and we can hardly resist the conclusion that a similar 

 transfer of other gases must also take place." 



Whatever view be correct as to the source and retention of 

 atmospheric hydrogen, there can be no. longer any doubt not 

 only of its presence but of its abundance, and the establishment 

 of this fact marks an advance in knowledge highly important 

 from many points of view. A. S. 



SCIENTIFIC AGRICULTURE IN THE UNITED 

 STA TES} 



A GRICULTURAL experiment stations are now in operation 

 under the act of Congress of March 2, 1887, in all the 

 States and Territories of the United States. Agricultural 

 experiments have been begun in Alaska with the aid of national 

 funds, and an experiment station is in operation in Hawaii 

 under private auspices. In each of the States of Alabama, 

 Connecticut, New Jersey and New York a separate station is 

 maintained wholly or in part by State funds, and in Louisiana a 

 station for sugar experiments is maintained partly by funds 

 contributed by sugar planters. Excluding the branch stations 

 established in the several States, the total number of stations 

 in the United States is 54. Of these 52 received the appro- 

 priation provided for in the act of Congress above mentioned. 

 The total income of the stations is about 1,143,334 dollars, of 

 which 720,000 dollars was received from the National Govern- 

 ment, the remainder, 423,334.93 dollars, coming from the 

 following sources : State Governments, 240,300.20 dollars ; 

 individuals and communities, 12,100 dollars; fees lor analyses 

 of fertilisers, 75,294.42 dollars ; sales of farm products, 69,312.60 

 dollars; miscellaneous, 26,327.71 dollars. In addition to this 

 the Office of Experiment Stations has an appropriation of 

 40,000 dollars for the past fiscal year, including 10,000 dollars 

 for the Alaskan investigation. 



The stations employ 678 persons in the work of administration 

 and inquiry. The number of officers engaged in the different 

 lines of work is as follows : — Directors, 71 ; chemists, 148; 

 agriculturists, 68 ; experts in animal husbandry, 9 ; horticul- 

 turists, 77 ; farm foremen, 21 ; dairymen, 23 ; botanists, 52 ; 

 entomologists, 48; veterinarians, 26; meteorologists, 17 ; bio- 

 logists, 7 ; physicists, 7 ; geologists, 5 ; mycologists and 

 bacteriologists, 20 ; irrigation engineers, 5 ; in charge of sub- 

 stations, 16; secretaries and treasurers, 24; librarians, 9; and 

 clerks, 43. There are also 48 persons classified under the 

 head of " miscellaneous," including superintendents of gardens, 

 grounds and buildings, apiarists, herdsmen, &c. Three hundred 

 and eight station officers do more or less teaching in the 

 colleges with which the stations are connected. 



During 1899 the stations published 445 annual reports and 

 bulletins, containing 16,924 pages. Besides regular reports and 

 bulletins, a number of the stations issued Press bulletins, which 

 were widely reproduced in the agricultural and county papers. 



In a recent report on the work and expenditures of the stations, 

 Mr. A. C. True, the Director of the Experiment Station Office, 

 makes the following general statements : — 



The work of the stations during the past year has for the 

 most part been along the same lines as heretofore, and in the 



1 Abridged from the Experiment Stdtion Record (\o\. xi. No. 9), pub 

 ished by the U. S. Department of Agriculturs. 



